Application of Subspace-Based Distorted-Born Iteration Method in Imaging Biaxial Anisotropic Scatterer

Various natural and artificial materials are anisotropic. The inverse scattering problem of anisotropic scatterers is widely involved in oil detection, nondestructive evaluation of composite materials and microscopic imaging of biological tissue. In this contribution, the two-dimensional inverse scattering problem of biaxial anisotropic scatterers illuminated by the TE-polarized incident wave is investigated. Since the biaxial anisotropic scatterer has different permittivity components along different transverse directions, the problem faced with is more complex than in the scalar TM-polarized case. The subspace-based distorted-Born iteration method (S-DBIM) is employed. Only one regularization term is involved in the inversion, which is proven to be quite robust against noise and flexible to be chosen. Both synthetic and experimental results are given to prove the validity of the proposed method. The results illustrate that as the interaction between the incident electric field and the scatterer induces a directional scattered field, the images constructed appear clear into the strongly scattered directions, but blurred into weakly ones. Overall, S-DBIM is shown to yield super-resolved images for the biaxial anisotropic scatterers, while being quite robust with respect to noise.